Real Madrid’s Cristiano Ronaldo celebrates after scoring their second goal against Barcelona in this file photo.

Manchester United vs Real Madrid takes place in the Champions League last 16 second leg on Tuesday night. The tie is all square at 1-1 after the first leg at the Bernabeu, and now the teams come to Old Trafford with Real boss Jose Mourinho saying, "The world will be watching." The game kicks off at 7.45 p.m. UK time and can be watched online through live stream (details below).

This tie is so evenly balanced that pundits are split 50:50 on who will come out on top tonight. Some believe that United's away goal gives them the upper hand coming to Old Trafford tonight. However, others point out that it would take an immense display of defensive discipline to keep out Real and in particular Cristiano Ronaldo for the entire 90 minutes tonight.

United boss Sir Alex Ferguson has said ahead of the game that his team cannot fear Ronaldo, and much has been billed about him being the pivotal player in deciding whether Real or Man. United come out on top tonight.

These two sides have met four times in the Champions League in the past, with the winner of the tie going on to win the competition on three of the four occasions.

(Photo: Reuters/Phil Noble)

Manchester United's Robin van Persie reacts after their English Premier League soccer match against Everton at Goodison Park in Liverpool, northern England, August 20, 2012.

For United, they have won 9 out of 12 games in Champions League ties where they gained an away draw in the first leg. For Real meanwhile, they have only ever gone through once in the Champions League after drawing their first leg tie at home. But that one time did in fact come against Manchester United in the 1999-2000 season.

It must also be remembered that United have conceded three goals in each of their last two home games against Real Madrid, giving a strong indication that Real will be able to wipe out and even turn the away goal advantage that United currently have on its head.

Manager-wise, Alex Ferguson vs Jose Mourinho has taken place 14 times in total, with Mourinho coming away with six win, Ferguson with just two wins, and six draws between the pair.

This should be a scintillating game, with the last two Champions League encounters, prior to their 1-1 draw in the Bernanbeu, producing 12 goals

All eyes will be on Ronaldo returning to Old Trafford - the place he used to call home and where he learnt his trade. However, it should not be forgotten that United's Ryan Giggs is set to play, meaning that at 39 years of age he will make his 1,000th career appearance.

Ferguson has said ahead of the game about Giggs, "He will be involved at some point, whether starting or on the bench I am not sure yet. His experience in these occasions will be vital to us."

Manchester United vs Real Madrid kicks off at 7.45 p.m. UK time and can be watched online through live stream on Fox Soccer by clicking here.